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238 lines
6.2 KiB
238 lines
6.2 KiB
/* infcodes.c -- process literals and length/distance pairs |
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* Copyright (C) 1995 Mark Adler |
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* For conditions of distribution and use, see copyright notice in zlib.h |
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*/ |
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#include "zutil.h" |
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#include "inftrees.h" |
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#include "infutil.h" |
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#include "inffast.h" |
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#include "infcodes.h" |
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/* simplify the use of the inflate_huft type with some defines */ |
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#define base more.Base |
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#define next more.Next |
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#define exop word.what.Exop |
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#define bits word.what.Bits |
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/* inflate codes private state */ |
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struct inflate_codes_state { |
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/* mode */ |
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enum { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */ |
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START, /* x: set up for LEN */ |
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LEN, /* i: get length/literal/eob next */ |
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LENEXT, /* i: getting length extra (have base) */ |
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DIST, /* i: get distance next */ |
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DISTEXT, /* i: getting distance extra */ |
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COPY, /* o: copying bytes in window, waiting for space */ |
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LIT, /* o: got literal, waiting for output space */ |
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WASH, /* o: got eob, possibly still output waiting */ |
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END, /* x: got eob and all data flushed */ |
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BADCODE} /* x: got error */ |
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mode; /* current inflate_codes mode */ |
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/* mode dependent information */ |
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uInt len; |
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union { |
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struct { |
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inflate_huft *tree; /* pointer into tree */ |
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uInt need; /* bits needed */ |
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} code; /* if LEN or DIST, where in tree */ |
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uInt lit; /* if LIT, literal */ |
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struct { |
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uInt get; /* bits to get for extra */ |
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uInt dist; /* distance back to copy from */ |
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} copy; /* if EXT or COPY, where and how much */ |
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} sub; /* submode */ |
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/* mode independent information */ |
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Byte lbits; /* ltree bits decoded per branch */ |
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Byte dbits; /* dtree bits decoder per branch */ |
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inflate_huft *ltree; /* literal/length/eob tree */ |
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inflate_huft *dtree; /* distance tree */ |
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}; |
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struct inflate_codes_state *inflate_codes_new(bl, bd, tl, td, z) |
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uInt bl, bd; |
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inflate_huft *tl, *td; |
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z_stream *z; |
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{ |
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struct inflate_codes_state *c; |
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if ((c = (struct inflate_codes_state *) |
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ZALLOC(z,1,sizeof(struct inflate_codes_state))) != Z_NULL) |
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{ |
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c->mode = START; |
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c->lbits = (Byte)bl; |
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c->dbits = (Byte)bd; |
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c->ltree = tl; |
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c->dtree = td; |
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Tracev((stderr, "inflate: codes new\n")); |
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} |
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return c; |
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} |
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int inflate_codes(s, z, r) |
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struct inflate_blocks_state *s; |
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z_stream *z; |
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int r; |
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{ |
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uInt j; /* temporary storage */ |
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inflate_huft *t; /* temporary pointer */ |
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int e; /* extra bits or operation */ |
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uLong b; /* bit buffer */ |
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uInt k; /* bits in bit buffer */ |
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Byte *p; /* input data pointer */ |
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uInt n; /* bytes available there */ |
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Byte *q; /* output window write pointer */ |
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uInt m; /* bytes to end of window or read pointer */ |
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Byte *f; /* pointer to copy strings from */ |
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struct inflate_codes_state *c = s->sub.codes; /* codes state */ |
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/* copy input/output information to locals (UPDATE macro restores) */ |
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LOAD |
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/* process input and output based on current state */ |
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while (1) switch (c->mode) |
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{ /* waiting for "i:"=input, "o:"=output, "x:"=nothing */ |
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case START: /* x: set up for LEN */ |
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#ifndef SLOW |
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if (m >= 258 && n >= 10) |
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{ |
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UPDATE |
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r = inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z); |
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LOAD |
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if (r != Z_OK) |
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{ |
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c->mode = r == Z_STREAM_END ? WASH : BADCODE; |
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break; |
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} |
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} |
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#endif /* !SLOW */ |
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c->sub.code.need = c->lbits; |
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c->sub.code.tree = c->ltree; |
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c->mode = LEN; |
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case LEN: /* i: get length/literal/eob next */ |
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j = c->sub.code.need; |
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NEEDBITS(j) |
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t = c->sub.code.tree + ((uInt)b & inflate_mask[j]); |
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DUMPBITS(t->bits) |
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if ((e = (int)(t->exop)) < 0) |
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{ |
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if (e == -128) /* invalid code */ |
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{ |
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c->mode = BADCODE; |
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z->msg = "invalid literal/length code"; |
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r = Z_DATA_ERROR; |
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LEAVE |
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} |
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e = -e; |
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if (e & 64) /* end of block */ |
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{ |
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Tracevv((stderr, "inflate: end of block\n")); |
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c->mode = WASH; |
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break; |
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} |
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c->sub.code.need = e; |
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c->sub.code.tree = t->next; |
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break; |
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} |
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if (e & 16) /* literal */ |
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{ |
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c->sub.lit = t->base; |
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Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ? |
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"inflate: literal '%c'\n" : |
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"inflate: literal 0x%02x\n", t->base)); |
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c->mode = LIT; |
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break; |
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} |
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c->sub.copy.get = e; |
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c->len = t->base; |
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c->mode = LENEXT; |
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case LENEXT: /* i: getting length extra (have base) */ |
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j = c->sub.copy.get; |
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NEEDBITS(j) |
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c->len += (uInt)b & inflate_mask[j]; |
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DUMPBITS(j) |
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c->sub.code.need = c->dbits; |
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c->sub.code.tree = c->dtree; |
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Tracevv((stderr, "inflate: length %u\n", c->len)); |
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c->mode = DIST; |
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case DIST: /* i: get distance next */ |
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j = c->sub.code.need; |
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NEEDBITS(j) |
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t = c->sub.code.tree + ((uInt)b & inflate_mask[j]); |
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DUMPBITS(t->bits) |
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if ((e = (int)(t->exop)) < 0) |
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{ |
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if (e == -128) |
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{ |
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c->mode = BADCODE; |
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z->msg = "invalid distance code"; |
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r = Z_DATA_ERROR; |
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LEAVE |
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} |
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c->sub.code.need = -e; |
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c->sub.code.tree = t->next; |
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break; |
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} |
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c->sub.copy.dist = t->base; |
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c->sub.copy.get = e; |
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c->mode = DISTEXT; |
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case DISTEXT: /* i: getting distance extra */ |
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j = c->sub.copy.get; |
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NEEDBITS(j) |
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c->sub.copy.dist += (uInt)b & inflate_mask[j]; |
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DUMPBITS(j) |
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Tracevv((stderr, "inflate: distance %u\n", c->sub.copy.dist)); |
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c->mode = COPY; |
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case COPY: /* o: copying bytes in window, waiting for space */ |
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f = (uInt)(q - s->window) < c->sub.copy.dist ? |
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s->end - (c->sub.copy.dist - (q - s->window)) : |
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q - c->sub.copy.dist; |
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while (c->len) |
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{ |
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NEEDOUT |
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OUTBYTE(*f++) |
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if (f == s->end) |
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f = s->window; |
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c->len--; |
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} |
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c->mode = START; |
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break; |
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case LIT: /* o: got literal, waiting for output space */ |
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NEEDOUT |
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OUTBYTE(c->sub.lit) |
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c->mode = START; |
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break; |
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case WASH: /* o: got eob, possibly more output */ |
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FLUSH |
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if (s->read != s->write) |
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LEAVE |
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c->mode = END; |
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case END: |
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r = Z_STREAM_END; |
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LEAVE |
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case BADCODE: /* x: got error */ |
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r = Z_DATA_ERROR; |
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LEAVE |
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default: |
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r = Z_STREAM_ERROR; |
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LEAVE |
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} |
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} |
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void inflate_codes_free(c, z) |
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struct inflate_codes_state *c; |
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z_stream *z; |
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{ |
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inflate_trees_free(c->dtree, z); |
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inflate_trees_free(c->ltree, z); |
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ZFREE(z, c); |
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Tracev((stderr, "inflate: codes free\n")); |
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}
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